Let me first say, that I don't have much experience with elapids, in regards to digestion, and none with king cobras specifically. But, that doesn't look healthy. Could be something eaten, parasites, who knows. But if that were a captive pet snake, I'd suggest getting a full fecal exam done to look for parasites, occysts, whatever they could find. Cryptosporidium is a likely candidate for causing that, but I'm not sure how common it its in wild asian reptiles, originally it was thought to be mostly a mammalian parasite, but in recent years certain strains (C. serpentes, etc...) have become common in captive reptile populations.
